Three men went off on a sailboat together, a physicist, a chemist, and an economist. Unfortunately they ran into a storm and the boat was wrecked on an uninhabited island. The only food they were able to rescue from the wreckage was a case of baked beans. As they got hungry, they began to wrestle with the problem of how to open the bean cans. The physicist said "I'll climb a tree and throw a can onto a rock and it'll split open." The others didn't much like this idea because they thought the beans would just splatter everywhere. The chemist said "We can soak the cans in salt water and they'll rust through." The others didn't much like this idea because it would take too long. Then the economist said "Hay--no problem, we'll just assume a can opener."